<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
  <style>
    #content{
      position: relative;
      top:30px
    }
    .return{
      position: relative;
        top:30px
    }
    #comments{
      width: 397px;
      height: 100px;
    }
    #con{
      position: relative;
      top:30px;
    }
    #cont{
      position: relative;
      width: 400px;
      height:150px ;
      top:30px;
      display: none;
    }
  </style>
  <script>
    function $(id) {
    return document.getElementById(id)
    }
    function aperra() {
      $('cont').style.display='block'
    }
    function clicks() {
         $('content').value = $('comments').value
         $('cont').style.display='none'
    }
  </script>
</head>
<body>
     <div style="width: 400px;height: 200px;border: 1px solid black">
       老师说：<br>
       <span style="font-size: 14px;font-weight: bold">今天考试客户端</span>
       <input type="text" name="content" id="content">
       <input class="return" type="button" value="回复" onclick="aperra()">
     </div>
     <div id="cont">
       <input type="text" value="" id="comments"><br>
       <input id="con" type="button"  value="评论" onclick="clicks()">
     </div>
</body>
</html>
